71

class Solution {
public:
    string simplifyPath(string path) {
        string res, tmp;
        vector<string> stk;
        stringstream ss(path);
        while(getline(ss,tmp,'/')) {
            if(tmp == "" or tmp == ".") continue;
            if(tmp == ".."){
                if(!stk.empty())
                    stk.pop_back();
            }
            else stk.push_back(tmp);
        }
        for(auto str : stk) res += "/"+str;
        return res.empty() ? "/" : res;
    }
};